During a yearlong investigation, the Post said it gathered documents showing more than 400 large U.S. military drones crashed in major accidents worldwide between Sept. 11, 2001, and December 2013.

In Nevada, the Post found, crashes involving at least 12 military drones worth at least $14 million had been reported since 2002.

The investigation, the Post said, challenges the federal government’s contention that drones will be able to fly safely over populated areas and share airspace with passenger planes.

Nevada has long pioneered the use of military drones. The Silver State is home to Creech Air Force Base, from which airmen piloted the Predator and Reaper drones in the Middle East.

In December, Nevada was named as one of six states by federal officials to develop test sites for drones. On June 9, Nevada became the third state to gain Federal Aviation Administration authorization to fly drones under a federal research program into unmanned aerial systems.

UNLV this fall is launching a minor degree program in unmanned aerial vehicles.

Unmanned Aircraft Systems are "the future of aviation, and there is no place better than Nevada to test these technologies safely, and at the same time, bring so many good-paying jobs to our state while doing so," U.S. Senate Majority Leader Harry Reid, D-Nev., said in a statement accompanying last week’s announcement.

"The authorization to fly is an exciting next step in the process to commercially integrate unmanned systems," Steve Hill, director of the Governor's Office of Economic Development, said in a statement after last week’s announcement. "I look forward to Nevada's continued leadership in this emerging industry."

A Predator (RQ-1L) owned by the Air Force crashed on Oct. 25, 2002

Reported location: 9 nautical miles west of Indian Springs Air Force Auxiliary Field, Nev.

Estimated damage: $3,300,000

What happened: A Predator on a training mission crashed into a Nevada mountain after the crew lost its control link. Air Force investigators blamed inattention on the part of the crew, finding that it was distracted by other tasks. "As soon as we regained line-of-sight, of course we saw the mountain in our path," one crew member testified. "We knew that at that point it was almost unrecoverable."

A Predator (MQ-1L) owned by the Air Force crashed on June 14, 2004

Reported location: Indian Springs Auxiliary Field, Nev.

Estimated damage: $4,200,000

What happened: A Predator with the call sign DEADLY01 crashed after a student pilot botched a landing exercise. Air Force investigators said that the pilot and his instructor aligned poorly for landing and that the crew did not request updated information about gusty conditions. The operations director for the 11th Reconnaissance Squadron had ordered extra training after a series of "tail-scrape" incidents in the weeks before

A Predator (MQ-1L) owned by the Air Force crashed on Sept. 22, 2004

Reported location: Indian Springs Auxiliary Field, Nev.

Estimated damage: $2,883,977

What happened: A Predator experienced a hard landing and nearly skidded off the runway. Investigators said the pilot reacted poorly because he was isolated in his ground-control station and could not feel the aircraft bumping on the runway or hear the scraping sounds of damaged landing gear.

A Predator (MQ-1) owned by the Air Force crashed on Feb. 1, 2006

Reported location: Nevada, United States

What happened: A Predator crashed after departure from Creech Air Force Base. The Air Force did not convene an Accident Investigation Board to produce a publicly releasable report.

A Predator (MQ-1L) owned by the Air Force crashed on June 22, 2006

Reported location: Creech Air Force Base, Nev.

Estimated damage: $4,700,000

What happened: Five minutes after takeoff, a Predator rapidly lost engine oil and the pilot intentionally crashed it into the side of a mountain to avoid falling on military personnel. Air Force investigators concluded that the cause was a loose oil filter that was likely installed improperly. Investigators said the student pilot did the right thing by intentionally crashing into the mountainside instead of risking a collision with people on the ground.

A Predator (MQ-1B) owned by the Air Force crashed on Aug. 3, 2006

Reported location: Nevada, United States

Estimated damage: $1,436,765

What happened: A Predator crashed on the runway after the instructor pilot botched a landing exercise. Air Force investigators determined the pilot thought he was raising the landing gear but hit the wrong switch and turned off the engine. The pilot also turned his head to talk to someone at the moment a warning message flashed on his screen. The pilot absent-mindedly pressed a button to confirm the command. The pilot tried to glide to a landing and "exercised profoundly poor judgment by remaining fixated on a course of action that he knew was destined to fail," investigators wrote. The pilot was forced by his employer to resign soon after, according to the report.

A Reaper (MQ-9A) owned by the Air Force crashed on Sept. 4, 2007

Reported location: Nevada, United States

What happened: The Air Force withheld information about the circumstances of this Reaper crash. The Air Combat Command did not convene an Accident Investigation Board to produce a publicly releasable report.

A Predator (MQ-1B) owned by the Air Force crashed on April 28, 2009

Reported location: 1.5 miles west of Creech Air Force Base, Nev.

Estimated damage: $543,178

What happened: A Reaper on a training mission crashed into desert terrain a minute after takeoff because of an engine malfunction. Investigators determined that a vacuum line to the carburetors became disconnected. The flight was the first for the Predator since its old engine had been replaced with a rebuilt model five days earlier. Investigators determined that the vacuum line had been installed correctly but that it was too short and subject to chafing. The pilot's skillful emergency landing saved the aircraft from being a total loss.

A Predator (RQ-1) owned by the Air Force crashed on June 12, 2009

Reported location: Nevada, United States

What happened: The Air Force withheld information about the circumstances of this crash. The Air Combat Command did not convene an Accident Investigation Board to produce a publicly releasable report.

A Reaper (MQ-9) owned by the Air Force crashed on May 20, 2011

Reported location: Creech Air Force Base, Nev.

What happened: A Reaper crashed after takeoff from Creech Air Force Base, but the Air Force withheld details of the circumstances. The Air Combat Command did not convene an Accident Investigation Board to produce a publicly releasable report.

A Reaper (MQ-9) owned by the Air Force crashed on Dec. 5, 2012

What happened: A Reaper crashed in an uninhabited area during a training exercise after going into a stall. Investigators determined that crew error was the primary cause. The ground-control station was improperly reconfigured from a setup for flying Predators to a setup for flying Reapers. When the pilot guided the throttle, it mistakenly triggered a reverse thrust because of the incorrect setup. "We're in the soup here," the pilot said, according to a voice-recording transcript. "Dude, uh, we're not sure what the aircraft is doing -- yeah, we crashed."

A Predator (MQ-1B) owned by the Air Force crashed on May 13, 2013

Reported location: 11 nautical miles west of Creech Air Force Base, United States

Estimated damage: $4,511,500

What happened: An unarmed Predator crashed during a training flight after the variable pitch propeller system failed. About five hours into a flight, the propeller pitch suddenly changed, causing reverse thrust as the aircraft plunged to the ground. "Okay, interesting. We are falling out of the sky," the pilot said, according to a voice-recorder transcript from the ground-control station. "Boy, this is going to be tight." Investigators concluded that the primary cause was a failure of the variable pitch propeller servomotor because of a bad electrical connection. Investigators concluded that a contributory factor was channelized attention on the part of the crew, which failed to notice that the propeller pitch had been locked in a fixed position for much of the flight.

Creech Air Force BaseCreech Air Force Base, Nev., is the home to the famed "Hunters" of the 432d Wing and 432d Air Expeditionary Wing. The base also hosts the operations of the 556th Test and Evaluation Squadron and 99th Ground Combat Training Squadron, and those of the Air Force Reserve's 78th Reconnaissance Squadron and Nevada Air National Guard's 232d Operations Squadron.